Real life iron bamboo! ...Sort of. Shifting mutation and all that jazz. Once the moisture drains out of the stalks, they become increasingly harder over time, resembling the metal they're named after. Better get them back to town quickly!

Other species might vary a little, but nothing exceptional. Do you have any specific type in mind?

Moon Stones are recognizable by the Pokefolk, yes. Though there might be a few actual moon-from-the-moon stones lying about. It's a very strange area...